Universal liner

ABSTRACT

The present invention relates to universal liner assemblies for use during hip joint replacement surgeries, kits providing a plurality of universal liners, and methods of manufacturing and implanting the universal liners. The universal liners allow the surgeon a greater degree of selection of liners and shells, without being tied to typical liner/shell connections based on material connection constraints.

This application claims priority to U.S. Provisional Patent ApplicationSer. No. 60/552,296, filed Mar. 11, 2004, the entire contents of whichare hereby incorporated by reference.

FIELD OF THE INVENTION

The present invention relates to universal liners that are particularlyuseful in joint replacement surgeries.

BACKGROUND

Orthopaedic implants are becoming increasingly prevalent as millions ofpatients have been treated for degenerative diseases and otherconditions that affect proper hip, knee, shoulder and other jointfunction. Surgery to replace a joint that articulates in a socket ofteninvolves removing the damaged parts of the relevant joint and replacingthem with prosthetic components.

For example, consider the hip. The hip joint is often called aball-and-socket joint because the spherical head of the thighbone(femur) moves inside the cup-shaped socket (acetabulum) of the pelvis.To duplicate this action, a hip replacement implant typically has astem, which fits into the femur and provides stability; a ball, whichreplaces the spherical head of the femur, and a cup, which replaces theworn-out hip socket. The cup typically features an acetabular shell anda liner.

Each component of the implant is typically provided in various sizes inorder to accommodate different body sizes and types. In some designs,the stem and ball are one piece; other designs are modular, allowing foradditional customization in fit. Typically, for cementless applications,a shell is implanted into the socket and a liner is implanted into theshell. A modular prosthetic stem is then implanted into the patient'sintramedullary canal and a head (or ball) is positioned on the stem. Thehead is also adapted to be positioned in the liner, so that theprosthetic is allowed to articulate in the liner, just as a bone wouldarticulate within a natural socket.

In choosing the joint implant components to use, a surgeon takes intoconsideration many factors, such as the patient's age, weight, andactivity level, as well as relevant factors relating to the implantitself, such as the type of liner to be used (e.g., ceramic, cross linedpolyethylene, ultra high molecular weight polyethylene, metal, and soforth) in conjunction with the type of shell (and thus the lockingconnection featured by the shell) to be used. The liner and shell aretypically chosen together because connections between liners and shellsare material-specific and design-specific.

For example, ceramic liner to metal shell (and metal liner to metalshell) connections typically use a Morse taper connection, which meansthat the outer surface of the liner is tapered slightly in order tocooperate with a corresponding taper on the inner surface of the shell.This allows the liner to lock in the shell via a secure connectionformed by the tapers.

By contrast, polyethylene liner to metal shell connections typically usea non-Morse taper connection because of the low push-out forceresistance of polyethylene. In other words, a Morse taper connection maynot secure a polyethylene liner to a metal shell because a taperedpolyethylene liner wants to “push” itself out of the shell. Polyethyleneliner to metal shell locking connections will vary, but two commonexamples are axial locking features and rotational locking features.

However, there may be instances in which the surgeon would prefer toselect the liner and the shell independently from one another, e.g., aparticular shell may have a preferred bone in-growth feature or acertain implantation feature, or a particular liner may have propertiesthat will be advantageous to that particular patient. A surgeon may notwant to use the type of liner that is adapted to cooperate with theparticular shell chosen and vice versa. One work-around method that hasbeen used by some surgeons is to apply cement to the pre-existing shellto secure a polyethylene liner. However, there is not currently a systemavailable that provides such flexibility.

Additionally, although many advancements have been made to prolong thelife of implants, joint implant surgeries may need to be repeated due tothe wear experienced by the artificial joint over prolonged periods oftime due. Wear debris can be generated from the articulating movement ofthe components against one another, the components may loosen, ceramicinserts may fail due to fracture, recurrent dislocation may occur, andso forth. During revision surgery, which is a surgery that replaces acurrent implant with a new one, the surgeon often needs to remove theshell, liner, and implant and replace them with new components.

One of the problems experienced with revision surgeries is that theshell, which may be have integrated into the patient's bone over time,has to be removed because the liner being used does not have connectingfeatures that correspond to those of the current shell and/or becausethe connecting features of the current shell are going to be damagedduring removal of the current liner.

For example, if the surgeon is planning to use a non-tapered liner, butthe currently-implanted shell is tapered, there is no way to create asecure connection. For instance, if a surgeon is removing a ceramicliner and chooses to replace it with a polyethylene liner, the surgeonwill have to remove the entire shell and replace it with a shell havinga different connection mechanism because the polyethylene liner likelywill not engage properly via a Morse taper. There is nothing to hold thepolyethylene liner in place, particularly because as polyethylene warmsup (e.g., due to body temperature), it expands and tends to pop out. Asdiscussed above, one alternative method of securing a non-fittingpolyethylene liner in place during revision surgery is to cement theliner to the cup, but that is not optimal.

Another example of why the shell often needs to be removed duringrevision surgery is because when the surgeon removes the initial liner(the one implanted during the primary surgery), even if the replacementliner has a connection that corresponds with the current shell, there isoften a threadform on the inner surface of the shell that is deformed ordamaged during removal of the initial liner. Although this threadformmay have helped to secure the initial liner, it will no longer beoperable to secure the replacement liner due to its deformation. This isparticularly a concern if the surgeon wishes to use a ceramic linerduring the revision surgery because the deformed threadform may create araised edge when the initial liner is removed, preventing a new ceramicliner from being properly received by the shell. A ceramic liner beingreplaced is at risk of either (a) being cracked or fractured on theraised edge of the threadform during replacement or (b) causing a higherrisk of fracture during prolonged use from cyclic fatigue against thedeformation.

Thus, it would be advantageous to provide a universal liner that cancooperate with a currently-implanted shell to cut down on trauma to thepatient due to removal of the shell. (Many shells are provided with abone in-growth material (such as a porous coating or a biologicalmaterial) that has encouraged the patient's bone to fuse with the shell.Accordingly, removal of the shell can cause unnecessary trauma to thepatient and removal of extra bone, neither of which are optimal.)

It would also be advantageous to provide a universal liner that givesthe surgeon more choices of liner to shell connection pre-operatively.

Accordingly, there is a need in the art for a more universal linerconnection.

SUMMARY

The present invention comprehends various embodiments of universal linerassemblies which may be employed, among other things, for use during hipjoint replacement surgeries. It also comprehends various kits providinga plurality of universal liners, as well as methods of manufacturing andimplanting the universal liners. It is beneficial for various implantcomponents used in connection with joint replacement surgeries to beinterchangeable, i.e., for liners of various materials to be able to beused with different types of shells. Additionally, because revisionsurgeries are common, it is particularly beneficial for a surgeon to beable to choose between universal liners of various materials that can beimplanted into a currently-implanted shell.

Embodiments of the universal liners described in this document provide aband assembly and a liner component that are assembled together andprovided as a one-piece universal liner. One of the benefits of suchuniversal liners is that the band portion interfaces with the innerportion of the shell, taking the specific material of the linercomponent (and thus the material-specific connection required for it tointerface with the shell) out of the equation.

The band portion may have one or more features that cooperate securelywithin the shell, such as a tapered slope that interfaces with a taperedshell, anti-rotation features on the band that interface with the lineror an inner portion of the shell, or other feature. The concept is thatthe band of the universal liner cooperates with and secures theuniversal liner within the inner portion of the shell.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a conceptual exploded perspective view of a universal lineraccording to certain embodiments of this invention and a side view of ashell adapted to receive the universal liner.

FIG. 2 shows a side perspective view of an assembled universal lineraccording to certain embodiments of the invention being inserted into ashell.

FIG. 3 shows a side perspective view of one embodiment of a band portionof a universal liner according to certain embodiments of the invention.

FIG. 4 shows a side perspective view of another embodiment of a bandportion of a universal liner according to certain embodiments of theinvention having anti-rotation structures.

FIGS. 5A-C show side perspective views of further embodiments of bandportions of a universal liner according to various embodiments of theinvention having anti-rotation structures and asperities.

FIG. 6A shows some alternate embodiments for anti-rotation structures.

FIG. 6B shows some alternate embodiments for asperities.

FIG. 7 shows a side view of a liner component adapted to cooperate witha band portion before assembly.

FIG. 8 shows an unassembled band and polyethylene liner component.

FIG. 9 shows an assembled universal liner according to certainembodiments of the invention.

FIG. 10A shows a side perspective view of an alternate embodiment of anunassembled band and ceramic liner component.

FIG. 10B shows a side perspective view of the components of FIG. 10A inan assembled configuration.

FIG. 10C shows a cut-away view of the assembled configuration of FIG.10B.

FIGS. 11-12 show alternate liners that may be used with universal linersaccording to various embodiments of the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 shows one embodiment of an assembly 10 according to certainaspects of the invention. Referring to FIG. 1, implant assembly 10features a universal liner 12 that comprises a band 20 and a linercomponent 40, and a shell 50. During a primary surgery, the outerportion 52 of shell 50 is implanted into a patient's acetabulum, thecup-shaped cavity at the base of the hipbone into which the ball-shapedhead of the femur fits. The specific type of shell 50 used is notessential because embodiments of this invention provide a universalliner 12 that can be used in conjunction with any number of shellembodiments 50. For ease of reference, a few features of various shellembodiments will nonetheless be described.

Shell 50 may be made from any biocompatible material that has sufficientstrength and wear resistance properties for prolonged use, such astitanium, titanium alloys, cobalt-chromium, surgical steel alloys, orother desired material. It may be press-fit (such that it fits in theprepared socket without cement) or it may be intended to be secured withcement. Shell 50 may have attachment structures 54 that may also receivefasteners used to secure shell 50 in place. Many shells 50 for use withceramic or metal liners have an inner surface 58 that is slightlytapered, such that it can receive a liner with a corresponding outertapered surface. Alternatively, shells intended for use with liners ofother materials, such as polyethylene, have other locking mechanisms.Shell may have bone in-growth features, such as a porous coating 56 ormesh holes to allow bone to grow into the mesh and essentially “becomepart of” the bone.

As shown in FIG. 2, the inner surface 58 of shell 50 is desirably highlypolished and mirror-like to reduce wear. See e.g., U.S. Pat. No.5,310,408, the contents of which are hereby incorporated by thisreference. (As discussed further below, the inner surface 32 of the bandmay also be highly polished.) Even the smallest amount of micro motionof the liner against the shell or the band can create wear particles anddebris, which can lead to osteolysis. Providing a highly polishedsurface on the shell and/or the band can prevent, reduce, or at leastslow the generation of debris.

Inner surface 58 may also feature a threadform 60, often a very thincircular or spiral protrusion within shell, which can be used to engagea liner. FIGS. 1 and 2 illustrate shell 50 in the form of a cup havingan outer rim 53 that is adapted to receive an assembled universal liner12.

Embodiments of universal liner 12 have two primary components, band 20and liner component 40. As shown in at least FIGS. 1-5 and 8-10, theband 20 has a height in a longitudinal direction and a thickness in aradial direction, where the height is greater than the thickness of theband. Band 20 and liner component 40 are manufactured together toprovide universal liner 12 to the end-user as a one-piece assembly 12,shown in FIGS. 2, 9 and 10B-C. (These figures show alternate embodimentsof bands according to various structures of the invention.)

In use, the outer surface of the band portion interfaces with the innerportion 58 of the shell 50, making the specific material of the linercomponent 40 (and thus the material-specific connection required for itto interface with the shell) irrelevant. The band is adapted tocooperate with the shell, regardless of the material of the linercomponent. As described in more detail below, the band portion may haveone or more features that cooperate securely within the shell, such as atapered slope that interfaces with a tapered shell, asperities on theband that interface with an inner portion of the shell, or otherfeature. The band may also have anti-rotation features that prevent itsrotational movement with respect to the shell 50.

As shown in FIG. 1, liner component 40 typically has a shape similar toshell 50, although the diameter of the outer surface 42 of linercomponent 40 is slightly smaller than the diameter of shell innersurface 58. This allows the liner component 40 to be received by shell50. Liner component 40 also forms an opening 44 that is adapted toreceive the head of an implant (not shown) and allow the head to slidesmoothly inside the acetabular implant. The surface of opening 44 mayalso be highly-polished or smooth to allow the implant head toarticulate naturally within liner component 40.

The liners shown in FIG. 1-10 are standard (or 0°) liners. Their openingsurface 44 is relatively flush with the shell 50 in use. All embodimentsof the invention described herein are also useable with wide chamferliners (an example of which is shown in FIG. 11), which in someinstances, can provide a greater range of motion, and anteversion liners(examples of which are shown in FIGS. 12A and 12B). Other types ofliners for use with this invention include overhang and lip liners. Ingeneral, any liner that is adapted to cooperate with a shell may be usedwith various embodiments of this invention.

Liner component 40 may be comprised of any biocompatible material,although common bearing materials include metal, cobalt-chromium,surgical steel, surgical steel alloys, diamond coated metal, ceramic,diamond coated ceramic, polyethylene (e.g., cross linked polyethylene,ultra high molecular weight polyethylene), biocompatible polymers,combinations thereof, or any other type of material having sufficientbiocompatibility, strength and wear resistance properties for prolongeduse. FIGS. 1 and 2 illustrate how liner outer surface 42 receives band20 or 120 to form universal liner 12. Band 20 is preferably seated suchthat it is in non-rotational relation to liner component 40. It has aninner seating surface 32 to cooperate with liner 40 and an outer seatingsurface 34 to cooperate with shell 50 in use.

The inner seating surface 32 of the band may also have a mirror-likepolished surface. In this embodiment, the shiny polished surface facesthe liner so that any relative motion between the liner and band willgenerate minimal liner debris. The polished surface has a roughness ofpreferably less than eight (8) micro inches.

As shown in FIG. 2, band 20 is assembled integrally around linercomponent 40. For the purposes of this application, “integral” and“integrally” are used to mean that the band is attached to the liner insuch a way that it is not easily removable and so that the universalliner is a one-piece assembly. Band may be formed of any biocompatiblematerial that has sufficient strength and wear resistance properties forprolonged use, such as titanium (including commercially-pure titanium),titanium alloys (including alloys with aluminum), cobalt-chromium,surgical steel, surgical steel alloys, PEEK (Polyetheretherketone),nitinol (a combination of nickel and titanium), other shape memory (orelastic) metals and alloys, combinations thereof, or other desiredmaterial. Various embodiments of band 20 are shown in FIG. 3-6.Additionally, although the bands are shown in the Figures as beingsomewhat symmetrical and round, it is possible for the bands to be anyshape that corresponds to the shape of the liner, e.g., oblong,egg-shaped, or any other shape that the liner may take.

FIG. 3 shows band 320 with exaggerated taper portions 26 forillustrative purposes only. In this embodiment, band 320 has a firstopen face 28 and a second open face 29, the faces defining an annularwall 30. Wall 30 provides a sloped or tapered portion 26 of band 320.Taper 26 is provided by wall 30 having a thickness that is greater atfirst face 28 than at second face 29. The sloped outer surface 26 ofband 320 is adapted to mate with the inner surface 58 of shell in Morsetaper-fashion, with the taper 26 of wall 30 acting as the male memberand the inner surface 58 of the shell 50 acting as the female member toreceive universal liner 12. Band 320 is shown in place on a linercomponent 40, shown in phantom.

In certain embodiments, there may be instances when the band 20 wouldbenefit from further rotational stabilization with respect to linercomponent 40. This is particularly useful with polyethylene liners.During formation of universal liner 12, the band and liner componentsare manufactured together to provide a one-piece unit 12. If, however,the connection is not rigid enough, there is a chance that band could“spin” or rotate slightly with respect to the liner, preventing a secureconnection of universal liner 12 in shell 50. FIG. 4-6 show variousembodiments of bands 120 designed to prevent such rotation.

FIG. 4 shows band 120 having anti-rotation features 22 that are formedin the lower portion 35 of band 120. Anti-rotation features 22 areadapted to cooperate with corresponding structures on liner (describedfurther below) to prevent rotation of band 120 around liner.Anti-rotation features 22 may be manufactured by cutting indented tabsin the lower portion 36 of a band, by providing protrusions on the band,or by any other method that will provide rotational locking betweenliner and band. In the embodiment shown in FIG. 4, anti-rotationfeatures 22 are V-shaped openings that are adapted to be received bycorresponding protrusions on the liner that cooperate with and “catch”anti-rotation features 22. As shown in FIG. 6A, anti-rotation features22 may be rounded, curved, square, triangular, trapezoidal, cone-shaped,or any other appropriate shape.

In the embodiment shown in FIG. 4, anti-rotation features 22 cooperatewith corresponding features 46 on liner when the two components areformed together. Corresponding features 46 of liner component 40 areshown in FIG. 2 as small protrusions or raised convolutions on linercomponent 40 at an area where the lower portion 36 of band 120 isseated. Alternate corresponding features 46 are shown in FIG. 7 asindentations that are shaped to receive a similarly-shaped feature onband. The indentations 46 on FIG. 7 form a ledge that is adapted toreceive anti-rotation features 22. It is understood that anti-rotationfeatures and corresponding features may be any shape, size, or structureadapted to secure two components together.

For example, as shown in FIGS. 5B and 5C, anti-rotation features 22 mayhave catches 38, which act as securing notches. Catches 38 are adaptedto cooperate with corresponding receivers 39 on liner 40, as shown inFIG. 7. In this embodiment, when band 120 is positioned over liner 40,catches 38 secure in receiver 39 to prevent liner 120 from rotatingaround liner 40 in use. Anti-rotation features 22 may alternatively beprovided by featuring indentations (or receivers) in the band andproviding corresponding protrusions (or catches) on the liner, or by anyother appropriate method.

Examples of alternate anti-rotation feature embodiments within the scopeof this invention include J-lock features (where either the band or theliner has a protrusion and the other component has a J-shaped groovethat engages and locks with the protrusion), keyed slots andcorresponding keys, dovetail locking mechanisms, ball and detentmechanisms, and any other features that will prevent one component fromrotating with respect to another component. Embodiments of anti-rotationfeatures secure rotation of the liner component 40 with respect to band20, 120, 220, 320.

FIGS. 5A, 5B, and 5C show band 220 having anti-rotation features 22, aswell as axial locking asperities 24. Bands according to variousembodiments of this invention may have anti-rotation features 22 alone,axial locking asperities 24 alone, neither, or both of these features.Bands having both of these features are shown and described in FIG.5A-5C.

FIG. 5A-5C show axial locking asperities 24 as cheese-grater-type teeth. Asperities 24 secure lock universal liner 12 with respect to shell 50.They are adapted to engage the inner surface 58 of the shell 50 in use,such that they flex to allow universal liner 12 to fully lock and secureitself within shell 50.

Asperities 24 can engage threadform 60, which may spiral within innersurface 58 of shell 50. Threadform 60 provides a series of edges for theasperities 24 to “grab” onto. (Note that the threadform may be deformeddue to removal of the previous liner in a revision surgery. Althoughthis deformation could present a challenge to liners that are currentlyavailable, certain embodiments of the universal liner 12 describedherein can use deformed threadform 60 as a securing ledge.) It isunderstood that asperities 24 may also be mashed inwardly as universalliner 12 is locked within shell 50, causing a resistant securing force.

Asperities 24 can also be used in conjunction with the taper embodiment(shown in phantom on FIG. 6A and described above) to confirm that thetaper is locked properly. For example, in order for the taper to befully locked, it is desirable that there be a bit of space between theouter surface 42 of the liner component 40 and the inner surface 58 ofthe shell 50; otherwise, there is a chance that the taper 26 is notfully engaged with the tapered sides of the shell. When a band 220having asperities 24 is used, the small amount of space is taken up bythe flexing asperities 24, assuring that the universal liner 12 isaxially locked within shell 50.

Although asperities 24 are shown as cheese-grater-type asperities 24 inFIG. 5, it is understood that asperities may be any type of projection,point, bump, rough surface, hook, or any other feature capable ofengaging with inner surface 58 and/or threadform 60 of shell 50. Asshown in FIG. 6B, asperities 24 may be provided in any shape (e.g.,triangular, square, rounded, or any other appropriate shape), as long asthey provide the desired axial locking between band 220 and shell 50.Asperities 24 may be manufactured by cutting or punching out portions ofband 120 and allowing them to bend outwardly, by being formed in theband, or by any other appropriate method.

Asperities 24 may be provided in rows (as shown in FIG. 5A-5C) or theymay be provided in random spacing order. In the particular embodimentshown in FIG. 5A, there are two rows of asperities 24 extending in alatitudinal direction around the band 220, each having twenty-fourasperities 24. FIG. 5B shows a combination of a complete row ofasperities 24 extending in a latitudinal direction around the band 220,along with a “broken” row of asperities 24. The “broken” row ofasperities 24 forms a row of two asperities 24 arranged in alongitudinal direction along the height of the band 220. FIG. 5C showsone row of larger asperities 24 extending in a latitudinal directionaround the band 220. Accordingly, asperities 24 may be provided in anysize and in any number, and in rows that extend in either a latitudinalor longitudinal direction around the band. For example, one largeasperity could flank the span of band or any number of asperities may beprovided in any spacing order on band.

Asperities may also be provided at any angle. The asperities 24 shown inFIG. 5A-5C are angled downward in order to provide axial locking. It isalso possible, however, for asperities to be angled further outward(e.g. angled at about 90° from the surface of the band 220) to alsoprovide rotational locking. It is possible to provide a row ofdownwardly-angled asperities along with a row of outwardly-angledasperities (or upwardly-angled asperities). Another embodiment would beto provide every other asperity at an alternate angle. Any otherplacement of asperities of various sizes and at alternate angles andorientations are within the scope of this invention.

FIG. 8 shows one embodiment of band 20 and a polyethylene linercomponent 40 prior to assembly. Any appropriate method that will secureband 20 to liner component 40 may be used. One manufacturing embodimentthat may be used with a polyethylene liner will be referred to as the“shrink-fit method.” Polyethylene shrinks when it is cooled, so in theshrink-fit method, the polyethylene liner component 40 is cooled tocause it to shrink to a size that is smaller than its actual size whenat room temperature. One possible method of cooling the liner is toimmerse it in liquid nitrogen. (Those of ordinary skill in the art willunderstand that there are many other cooling and manufacturing methodspossible.)

Once the polyethylene liner component 40 is sufficiently cooled, band 20(or any of embodiments 120, 220, 320) is fitted over the cooledpolyethylene liner component 40 to form universal liner 12, oneembodiment of which is shown in FIG. 9. Although the lock is tight atthis point, as the polyethylene liner warms, the lock is furtherenhanced. The lock is often further enhanced when universal liner 12 isimplanted due to increased temperature from the patient's body heat, andthus, increased expansion of liner component 40.

Alternatively, band may be a long strip that is applied to the outersurface of liner by any appropriate method, such as welding, sealing,chemical adhesion, laser etching, etc.

FIG. 10A shows one embodiment of band 20 and a ceramic liner component40 prior to assembly. Again, any appropriate method that will secureband 20 to liner component 40 may be used. One manufacturing embodimentthat may be used with a ceramic liner will be referred to as the“vacuum/pressure method.” The ceramic liner component 40 may besubjected to a certain amount of pressure, allowing the band 20 to befit circumferentially around liner. When pressure is released, the band20 is integrally seated on liner component 40, as shown in FIG. 10B.Other manufacturing methods include thermal expansion, press fit, orrolling the edges of the band over the circumference of the liner.Additional manufacturing methods would be apparent to those skilled inthe art and considered within the scope and spirit of this invention.

FIG. 10C shows an embodiment of a ceramic universal liner 12 with aceramic liner component 40 having a tapered side 43. Tapered side 43features a taper that is shorter than a typical ceramic liner taper,allowing more room inside the metal shell to receive liner, although itis understood that taper may be any desired length. Additionally, band20 is shown with a tapered surface 26 that does not extend up the entireside 43 of liner 40. This also opens up more room inside the metal shellto receive universal liner 12. (Features that take up less room insidethe metal shell allow for the use of larger liners, which allows for theuse of larger prosthetic heads, which provides greater range of motionand decreased risk of dislocation.) In the embodiment shown, theinterface between the band and the liner accordingly does not take placeover the entire outer surface 42 of liner, but instead, is focused onliner side 43. This allows universal liner 12 to cooperate with shell 50in a secure manner, while also providing more space within shell,allowing the use of a larger liner 12.

The description will now turn to how the universal liner is implanted.During a hip replacement surgery, the surgeon makes an incision over thehip joint. The ligaments and muscles are then separated to allow thesurgeon access to the bones of the hip joint. If this is a primarysurgery (i.e., not a revision surgery), the femoral head is dislocatedfrom the acetabulum. The natural femoral head is typically removed bycutting through the femoral neck. After the femoral head is removed,cartilage is removed from the acetabulum. The reamer or drill used toremove cartilage may also be used to form the bone in a hemisphericalshape to fit the metal shell portion of the acetabular component.

Before implanting the actual shell component, the surgeon will typicallyuse a trial component (a duplicate of the hip prosthesis) to ensure thatthe intended prosthesis is a good fit. The acetabular shell is theninserted into place using one or more of an impactor, bone screws, orcement.

If the surgeon is conducting a revision surgery, it may be necessary toremove the ball and stem prosthesis and/or remove the liner from theshell. If the surgeon is using a universal liner according toembodiments of the invention, it will not always be necessary to removethe shell from the patient's bone socket because the universal liner isadapted to cooperate with many if not all commercially available shells,regardless of what type of liner it was initially designed for use with.

One particular embodiment of the invention provides a polyethylene-typeuniversal liner that can be installed into an implanted shell that wasdesigned for use with, and originally implanted with, a ceramic liner.Another embodiment provides a ceramic or other non-polyethylene-typeuniversal liner that can be installed into a shell that is currentlyimplanted in a patient.

Once the proper universal liner is chosen, the surgeon will place theuniversal liner inside the metal shell, typically using an impactor. Oneof the advantages of this procedure is that the surgeon is able toselect the metal shell to be used independently from selecting theuniversal liner.

To begin replacing the femoral head, rasps are used to shape and hollowout femur to the exact shape of the metal stem of the femoral component.A trial component may be used again to confirm the correct size andshape of the prosthesis chosen. The surgeon will also test the movementof the hip joint.

Once the size and shape of the canal exactly fit the femoral component,the stem is inserted into the femoral canal. If an uncemented femoralstem is to be used, it is held in place by the tightness of the fit intothe bone. If a cemented femoral stem is to be used, the femoral canal israsped to a size slightly larger than the femoral stem. Then epoxy-typecement is used to secure the metal stem to the bone. Finally, the metalball that replaces the femoral head is attached to the femoral stem. Asa final step, the surgeon will typically check the location of theprosthesis with an x-ray or C-arm image.

Changes and modifications, additions and deletions may be made to thestructures and methods recited above and shown in the drawings withoutdeparting from the scope or spirit of the invention and the followingclaims.

1. A universal liner assembly for use with a shell having an innersurface and an outer rim, comprising: (a) a liner component having anouter surface; and (b) a band having a continuous annular wallconfigured to be formed around a portion of the outer surface of theliner component such that, in use, the band is adapted to interface withthe inner surface of the shell without extending beyond the outer rim ofthe shell and to lock the liner component within the shell, regardlessof the material of the liner component, the band comprising a pluralityof cut out portions defining a plurality of openings extending throughthe band, wherein the plurality of cut out portions comprisecheese-grater-type asperities.
 2. The universal liner assembly of claim1, wherein a portion of the annular wall of the band comprises a taperedouter seating surface, wherein the inner surface of the shell comprisesa tapered inner seating surface, and wherein the tapered outer seatingsurface of the band is adapted to cooperate with the tapered innerseating surface of the shell.
 3. The universal liner assembly of claim1, wherein the band comprises a plurality of anti-rotation features andthe liner component comprises a plurality of corresponding anti-rotationfeatures.
 4. The universal liner assembly of claim 3, wherein theanti-rotation features comprise a series of catches and receiversadapted to engage the liner component and band in non-rotationalalignment.
 5. The universal liner assembly of claim 3, wherein theanti-rotation features comprise (a) a plurality of openings on the bandthat cooperate with a plurality of protrusions on the liner component,(b) a plurality of protrusions on the band that cooperate with aplurality of indentations on the liner component, or (c) a combinationthereof.
 6. The universal liner assembly of claim 1, wherein the innersurface of the shell has a threadform and the plurality of cut outportions define axial locking features that engage the threadform tosecure the universal liner assembly in place.
 7. The universal linerassembly of claim 1, wherein the band has an inner seating surfaceadapted to cooperate with the outer surface of the liner component, andwherein the inner seating surface of the band is highly polished andadapted to reduce wear.
 8. The universal liner assembly of claim 1,wherein the universal liner assembly is adapted for use during arevision surgery and can be received by a shell that is currentlyimplanted in a patient.
 9. The universal liner assembly of claim 1,wherein the band comprises titanium, titanium alloys, cobalt-chromium,surgical steel, surgical steel alloys, PEEK (Polyetheretherketone),nitinol, shape memory metals, or any combinations thereof.
 10. Theuniversal liner assembly of claim 1, wherein the liner componentcomprises metal, cobalt-chromium, surgical steel, surgical steel alloys,diamond coated metal, ceramic, diamond coated ceramic, polyethylene,biocompatible polymers, or any combinations thereof.
 11. The universalliner assembly of claim 1, wherein the band is dimensioned to retain theliner component in place within the shell.
 12. A universal linerassembly for use with a shell having an inner surface comprising: (a) aliner component having an outer surface; and (b) a band configured to beformed around a portion of the outer surface of the liner component suchthat, in use, the band is adapted to interface with the inner surface ofthe shell to lock the liner component within the shell, regardless ofthe material of the liner component, the band comprising an outersurface and a plurality of cut out portions defining a plurality ofopenings extending through the band, wherein the plurality of cut outportions comprise cheese-grater-type asperities, and wherein the outersurface of the band comprises a tapered outer seating surface, whereinthe inner surface of the shell comprises a tapered inner seatingsurface, and wherein the tapered outer seating surface of the band isadapted to cooperate with the tapered inner seating surface of theshell, and wherein the band has first and second open faces defined byan annular wall, the annular wall having a first thickness at the firstface that is greater than a second thickness at the second face.
 13. Auniversal liner kit, comprising: a plurality of liner and bandassemblies, each assembly comprising a liner component with a bandconfigured to be assembled around a portion of the liner component,wherein, in use, each assembly is dimensioned to receive a sphericalimplant, wherein the liner components are provided in a plurality ofmaterials selected from the group consisting of metal, cobalt-chromium,surgical steel, surgical steel alloys, diamond coated metal, ceramic,diamond coated ceramic, or any combinations thereof, and wherein theband comprises a plurality of cut out portions defining a plurality ofopenings extending through the band, and wherein the plurality of cutout portions comprise cheese-grater-type asperities, and wherein theband has first and second open faces defined by an annular wall, theannular wall having a first thickness at the first face that is greaterthan a second thickness at the second face.
 14. The universal liner kitof claim 13, wherein at least one of the bands comprises a sloped outersurface adapted to cooperate with a tapered inner surface of a shell.15. The universal liner kit of claim 13, wherein at least one of thebands comprises an anti-rotation feature.
 16. The universal liner kit ofclaim 15, wherein the anti-rotation feature comprises (a) openings onthe band that cooperate with protrusions on the liner component, (b)protrusions on the band that cooperate with indentations on the linercomponent, or (c) a combination thereof.
 17. The universal liner kit ofclaim 13, further comprising a set of instruments adapted to place aliner and band assembly within a shell.
 18. The universal liner kit ofclaim 13, further comprising a shell component adapted to receive one ofthe plurality of liner and band assemblies.
 19. The universal liner kitof claim 18, wherein the plurality of cut out portions comprise aplurality of axial locking features that engage the shell to secure theliner and band assembly within the shell.
 20. A universal linerassembly, comprising: (a) a liner component having an outer surface; and(b) a band having (i) a plurality of anti-rotation features adapted tocooperate with the outer surface of the liner component and (ii) aplurality of cut out portions defining a plurality of openings extendingthrough the band, wherein the plurality of cut out portions comprisecheese-grater-type asperities and are adapted to cooperate with a shellto lock the liner component in place, such that, in use, the universalliner assembly is dimensioned to receive a spherical implant and theband is adapted to interface with and secure the liner component in ashell that was initially designed for use with a liner of a differentmaterial, wherein the band has first and second open faces defined by anannular wall, the annular wall having a first thickness at the firstface that is greater than a second thickness at the second face.
 21. Theuniversal liner assembly of claim 20, wherein the universal linerassembly is adapted to cooperate with a shell that was initiallydesigned for use with a ceramic or metal liner, and wherein the shellcomprises an inner surface that is tapered.
 22. A method of performing ajoint revision implant surgery in a patient's hip socket, comprising:(a) leaving a shell from a previous surgery in place in the patient'ship socket, the shell comprising an inner surface; and (b) placing auniversal liner in the shell, the universal liner comprising: (i) aliner having an outer surface; and (ii) a band configured to be formedaround a portion of the outer surface of the liner such that, in use,the band is adapted to interface with the inner surface of the shell andlock the liner within the shell, regardless of the material of theliner, the band having a plurality of cut out portions defining aplurality of openings extending through the band, wherein the pluralityof cut out portions comprise cheese-grater-type asperities, and whereinthe band has first and second open faces defined by an annular wall, theannular wall having a first thickness at the first face that is greaterthan a second thickness at the second face.
 23. A universal linerassembly for use with a shell having an inner surface, comprising: (a) aliner component having an outer surface; and (b) a generally cylindricalband having a height in a longitudinal direction and a thickness in aradial direction, wherein the height of the band is greater than thethickness of the band, the band configured to be formed around a portionof the outer surface of the liner component such that, in use, theuniversal liner assembly is dimensioned to receive a spherical implantand the band is adapted to interface with the inner surface of the shelland lock the liner component within the shell, regardless of thematerial of the liner component, the band comprising a plurality of cutout portions defining a plurality of openings extending through theband, and wherein the plurality of cut out portions comprisecheese-grater-type asperities.
 24. A universal liner assemblycomprising: a shell comprising an inner surface, a plurality of ridgesprotruding from the inner surface, and an outer rim; a liner componentcomprising an outer surface and an apex; and a band comprising acontinuous annular wall and a plurality of cut out portions defining aplurality of openings extending through the annular wall, wherein theplurality of cut out portions comprise a plurality of cheese-grater-typeasperities , wherein the band is configured to be formed around aportion of the outer surface of the liner component, and wherein theliner component and the band are received within the shell withoutextending beyond the outer rim of the shell, and the plurality ofasperities of the band engage with the plurality of ridges of the shellto thereby lock the liner component within the shell, regardless of thematerial of the liner component.
 25. The universal liner assembly ofclaim 24, wherein the plurality of asperities on the band are arrangedin a plurality of rows positioned around a circumference of the band.26. The universal liner assembly of claim 25, wherein asperities from aplurality of the rows engage with ridges on the inner surface of theshell.
 27. The universal liner assembly of claim 25, wherein theplurality of rows extend in a latitudinal direction around the band. 28.The universal liner assembly of claim 25, wherein the plurality of rowsextend in a longitudinal direction on the band.
 29. The universal linerassembly of claim 24, wherein the plurality of ridges protruding fromthe inner surface of the shell comprise a threadform.
 30. An assemblycomprising: (a) a shell having an inner surface and an outer rim; and(b) a universal liner comprising: (i) a liner component comprising anouter surface; and (ii) a band comprising a continuous annular wall thatextends around the outer surface of the liner component, and furthercomprising cut out portions defining a plurality of openings extendingthrough the annular wall, wherein the plurality of cut out portionscomprise cheese-grater-type asperities, wherein, in use, the universalliner is positioned within the shell so that the band interfaces withthe inner surface of the shell to lock the liner component within theshell, regardless of the material of the liner component, and wherein,in use, the universal liner is dimensioned to receive a sphericalimplant.
 31. The universal liner assembly of claim 30, wherein the bandis adapted to interface with the inner surface of the shell withoutextending beyond the outer rim of the shell.
 32. The universal linerassembly of claim 30, wherein the shell comprises a plurality of ridgesprotruding from the inner surface, and wherein at least some of theplurality of asperities of the band engage at least some of theplurality of ridges of the shell to thereby lock the liner componentwithin the shell.
 33. The universal liner assembly of claim 32, whereinthe plurality of asperities on the band are arranged in a plurality ofrows positioned around a circumference of the band.
 34. The universalliner assembly of claim 33, wherein asperities from a plurality of therows engage with ridges on the inner surface of shell.
 35. The universalliner assembly of claim 30, wherein, in use, the entirety of the band ispositioned between the inner surface of the shell and the outer surfaceof the liner component.
 36. The universal liner assembly of claim 30,wherein the band further comprises a first open face, a second openface, and a plurality of openings that extend through the annular wallof the band from the first open face towards the second open face.